Prognostic Significance of the Estimated Small Dense Low-Density Lipoprotein Cholesterol Levels in Predicting the Incidence of Coronary Artery Disease: The Nagahama Study and Shizuoka Kokuho Database Study.

Abstract

Aims: Small dense low-density lipoprotein cholesterol (sdLDLC) has been suggested to be more harmful for cardiovascular outcomes than total LDLC. This study aimed to clarify the prognostic significance of the estimated sdLDLC for the incidence of coronary artery diseases (CAD).

Methods: We analyzed the clinical information obtained at an annual health checkup of 365,083 adults aged 40-74 years enrolled in the National Health Insurance system in Japan. The incidence of CAD was determined using the health insurance claims data. Additionally, we calculated Japanese-specific coefficients of the sdLDLC estimation equation using general population data, where the measured sdLDLC value was available (n = 9,558).

Results: The estimated sdLDLC level calculated from the total LDLC and triglyceride levels was correlated with the measured sdLDLC level (coefficient of determination = 0.768) and it was significantly associated with the CAD incidence (hazard ratio per 10 mg/dL = 1.21, p＜0.001). Although the total LDLC showed a similar association, the estimated sdLDLC ≥ 30 mg/dL (hazard ratio = 1.97, p = 0.016) and ≥ 40 mg/dL (hazard ratio = 2.57, p = 0.001) were significantly associated with CAD, even in participants with normal LDLC levels (＜120 mg/dL). The cross-sectional association of the measured sdLDLC with the pulse wave velocity of the large artery (β = 0.034, p＜0.001) was significant, while that of the estimated sdLDLC (β = 0.014, p = 0.057) was not.

Conclusion: The estimated sdLDLC may be a straightforward and cost-effective marker for identifying individuals with normal LDLC levels at risk of CAD. However, the measured sdLDLC may be a more favorable marker than the estimated sdLDLC.